2.6.28-stable review patch. If anyone has any objections, please let us know.

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From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

(cherry picked from commit d794bf8e0936dce45104565cd48c571061f4c1e3)

When creating a new ext4_prealloc_space structure, we have toinitialize its list_head pointers before we add them to any prealloclists. Otherwise, with list debug enabled, we will get listcorruption warnings.